JP2015089313A - Rotating electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor, having a plurality of magnets with different magnetic force characteristics inserted in line into a magnet insertion hole of a rotor, which allows easy checking of the magnet arrangement order and a reduced manufacturing cost.SOLUTION: A rotor core 4 of a motor 2 has a magnet insertion hole 4a extending in a rotor axial direction. Three or more magnet pieces 5a to 5c with different magnetic force characteristics are inserted in the magnet insertion hole 4a such that they are aligned in the rotor axial direction. When the plurality of magnet pieces 5a to 5c are inserted in line into the magnet insertion hole 4a, an outermost end face St in a direction of a rotor axis CL is not parallel to end faces Sa and Sb which are other end faces, in the rotor axial direction, than the outermost end face St. If the order of magnet insertion is wrong, then the non-parallel opposite faces are arranged to face each other, thereby creating a gap. This makes an operator realize that the insertion order is wrong.

Description

  The present invention relates to a rotating electrical machine.

  In recent years, with the spread of hybrid vehicles and electric vehicles, there is an increasing demand for performance improvement for motors for running (rotary electric machines). As one of the improvements in motor performance, Patent Document 1 proposes a technique in which a magnet used for a rotor is composed of a plurality of magnets having different coercive forces. In this technique, a plurality of magnets having different coercive forces are arranged in the rotor axial direction in the rotor axial direction. More specifically, a magnet having a relatively low coercive force is disposed in a portion having a high heat dissipation property, and a magnet having a relatively high coercive force is disposed in a portion having a low heat dissipation property. The technology of Patent Document 1 arranges magnets having different coercive forces according to the position of the rotor in the axial direction, and improves the performance of the motor. In addition, the manufacturing method of such a magnet with different coercive force is disclosed by patent document 2, for example.

JP 2013-132116 A JP2013-158183A

  In the technique of Patent Document 1, when a plurality of magnets having different coercive forces are sequentially inserted into one magnet insertion hole, the magnets to be inserted are arranged in order so that the magnets having the predetermined coercive force are arranged at the predetermined positions. It is necessary to pay attention. If the outer shapes of the plurality of magnets are the same, there is a possibility that the insertion order may be wrong, and that the wrong order cannot be determined from the appearance. In particular, since there is a large difference in holding force between the magnet arranged at the end in the axial direction of the rotor and the magnet arranged outside the end, the magnet that should originally be arranged at the end of the rotor core is arranged at another position. If this happens, the performance of the motor will be significantly different from the planned performance. The present specification relates to a motor in which a plurality of magnets are arranged in a rotor axial direction inside a rotor core, and a technique for easily preventing a magnet to be arranged at an end portion in the rotor axial direction from being mistakenly arranged at a different position. I will provide a. Since it is possible to easily prevent errors in the magnet placement position, the assembly work load is reduced and manufacturing costs are reduced, or a motor with a wrong magnet placement position is not manufactured, resulting in an increase in manufacturing yield. The advantage is obtained.

  The motor disclosed in the present specification includes a rotor (rotor core) having a magnet insertion hole extending in the rotor axial direction, and three or more magnets having different magnetic properties that are inserted in the magnet insertion hole side by side in the rotor axial direction. Is provided. When the plurality of magnets are inserted side by side in the magnet insertion hole, the outermost end surface in the rotor axial direction and the other end surface in the rotor axial direction other than the outermost end surface are nonparallel. In other words, the end surface in the rotor axis direction is an end surface that intersects with a straight line parallel to the rotor axis. In such a motor, if a magnet that should originally be positioned at the end in the rotor axial direction is mistakenly disposed at a position other than the end, a gap is created between the magnet and the magnet disposed adjacent to the end, and all magnets Does not fit properly. Therefore, the assembly operator can immediately notice that the insertion order of the magnets is wrong.

  According to the technology disclosed in this specification, a motor in which a group of magnets having different coercive forces between a magnet at the end in the rotor axial direction and a magnet other than the end is arranged in one magnet insertion hole of the rotor is provided at the end. It is possible to easily prevent the magnet to be arranged from being mistakenly arranged at another position.

  Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

1A is a side view of the rotor of the motor according to the first embodiment, and FIG. 1B is a cross-sectional view taken along the line BB of FIG. 1A. It is sectional drawing in the II-II line of FIG. 1 (B). It is an expanded sectional view of the magnet of 1st Example. It is sectional drawing of the rotor of 2nd Example. It is an expanded sectional view of the magnet of 2nd Example.

  (First Embodiment) A motor 2 (rotary electric machine) of the first embodiment will be described with reference to the drawings. FIG. 1 shows the rotor 3 of the motor 2. Since the motor 2 disclosed in this specification is characterized by the rotor 3, illustration and description of the stator are omitted. 1A is a side view of the rotor 3, and FIG. 1B is a cross-sectional view taken along the line BB of FIG. 1A. In addition, the code | symbol CL of FIG. 1 represents a rotor axis line.

  The rotor 3 includes a rotor core 4 made by stacking thin circular magnetic steel plates, and a shaft 12 that penetrates the center of the rotor core 4 in the axial direction thereof. The rotor core 4 is sandwiched between end plates 14 at both ends, and is further fixed to the shaft 12 with nuts 13 from both sides of the end plate 14.

  The rotor core 4 is provided with a plurality of magnet insertion holes 4a penetrating in the rotor axial direction. Eight magnet insertion holes 4a are provided at equal intervals in the circumferential direction of the rotor. A magnet 5 (permanent magnet) is inserted into each magnet insertion hole 4a. The magnet 5 extends from one end of the rotor core 4 to the other end, is restrained on both sides by the end plate 14, and does not jump out of the rotor core 4.

  FIG. 2 is a cross-sectional view taken along the line II-II in FIG. In FIG. 2, hatching indicating a cross section of the rotor core 4 is omitted for easy understanding of the drawing. Further, as described above, the rotor core 4 is formed by laminating thin magnetic steel plates, but in FIG. 2, illustration of lines for distinguishing individual laminated steel plates is also omitted.

  The magnet 5 inserted into one magnet insertion hole 4a is divided into a plurality of magnet pieces 5a, 5b, and 5c. In other words, in this embodiment, the plurality of magnet pieces 5a-5c are collectively referred to as magnets 5. The plurality of magnet pieces 5a-5c have different magnetic properties. In FIG. 2, the difference in magnetic characteristics is represented by the difference in hatching. The magnetic characteristics will be described later.

  The magnet pieces 5a-5c are arranged in a row in the magnet insertion holes 4a extending along the rotor axis CL. Adjacent magnet pieces oppose each other in parallel planes, and the plurality of magnet pieces 5a-5c are arranged without gaps. Hereinafter, in each magnet piece, a surface that intersects a straight line parallel to the rotor axis CL is referred to as an end surface. Hereinafter, in order to simplify the description, “a plane intersecting a straight line parallel to the rotor axis CL” is simply expressed as “a plane intersecting the rotor axis CL”. The outermost end surfaces St of the plurality of magnet pieces 5a-5c arranged in a row are also one of the end surfaces.

  As shown in FIG. 2, the outermost end faces St are orthogonal to the rotor axis CL, but are opposed to the other end faces (both end faces Sa and Sb of the magnet piece 5b, and further to the end face of the magnet piece 5b). End face of the magnet piece 5a and end face of the magnet piece 5c) obliquely intersect the rotor axis CL. In the following, the end face of the magnet piece 5a that faces the end face Sa of the magnet piece 5b is also referred to as “end face Sa”, and the end face of the magnet piece 5c that faces the end face Sb of the magnet piece 5b is also called “end face”. This is referred to as “Sb”. Therefore, in other words, when the plurality of magnet pieces 5a-5c are inserted side by side in the magnet insertion hole 4a, the outermost end surface St in the rotor axis CL direction and the other axial direction other than the outermost end surface The end surfaces Sa and Sb are non-parallel.

  With reference to FIG. 2, the example of the difference of the end surface of the axis line CL direction of each magnet piece is demonstrated. Opposing end surfaces Sa of the pair of magnet pieces 5a and 5b are planes inclined with respect to the rotor axis CL. The opposing end surfaces Sb of the pair of magnet pieces 5b and 5c are also flat surfaces inclined with respect to the rotor axis CL. In other words, the end surfaces Sa and Sb are inclined with respect to the axis orthogonal plane. The end surfaces Sa and Sb are parallel. On the other hand, the outermost end surface St of the group of magnet pieces 5a-5c is orthogonal to the rotor axis CL. Due to this feature, if the magnet piece 5a or 5c that should originally be arranged at the end is mistakenly inserted into the rotor core 4, a gap is formed between adjacent magnet pieces. Therefore, the operator who inserts the magnet pieces can immediately notice that the insertion order is wrong. Therefore, in the motor 2 of the embodiment, it is easy to insert a plurality of magnets in which the insertion order of the rotor core 4 into the magnet insertion hole 4a is predetermined.

  The magnet pieces 5a-5c have different magnetic characteristics. This will be described. In the rotor core 4, magnets 5 extending from end to end along the rotor axis CL are arranged at equal intervals in the circumferential direction. The motor 2 enhances the performance of the motor by changing the magnetic properties of the magnet pieces 5a-5c according to the position in the rotor axial direction. The magnetic characteristics of the magnet 5 (magnet pieces 5a-5c) will be described with reference to FIG. FIG. 3 is a longitudinal sectional view of the magnet 5. The magnet 5 has a high coercive force on the outer side thereof, and the coercive force becomes lower toward the inner center. In FIG. 3, dark gray indicates the high coercive force region Ma, light gray indicates the medium coercive force region Mb, and white regions indicate the low coercive force region Mc. The higher the coercive force of the magnet, the lower the magnetic flux density passing through it. Therefore, the magnet 5 has a higher magnetic flux density through which the inside passes than the outside. By adopting the magnet 5 having such a magnetic force characteristic depending on the position in the rotor axial direction in the rotor, the cost performance of the motor is improved as described below.

  As shown in FIG. 3, in the magnet pieces 5 a and 5 c to be arranged at the end of the rotor core, the entire end surface St located on the outermost side in the axis CL direction of the rotor core 4 is a high coercive force region Ma. On the side, a high coercive force region Ma, a medium coercive force region Mb, and a low coercive force region Mc are mixed. Therefore, if such magnet pieces 5a and 5c are arranged at positions other than the original arrangement positions, the planned motor performance cannot be exhibited. As described above, in the motor 2, the outermost end surface St and the other end surfaces Sa and Sb are non-parallel. Therefore, if the magnet pieces 5a and 5c that should originally be positioned at the end portion of the rotor core in the direction of the axis CL are erroneously arranged inside in the direction of the axis CL, a gap is generated between the magnet pieces and the magnet pieces are inserted. The operator can immediately notice that the insertion order is wrong. In the magnet piece 5b, the magnetic force characteristics are parallel along the axis CL, and the magnetic force characteristics are the same even when the magnet pieces 5b are rotated 180 degrees. Therefore, both end surfaces Sa and Sb of the magnet piece 5b may be parallel.

  In the magnet 5 extending from end to end of the rotor core 4 along the rotor axis CL, the coercive force of the magnet surface layer is preferably high, but the internal coercive force does not contribute so much to the performance of the motor. In order to increase the coercive force, it is preferable to increase the content of Dy (dysprosium) and Tb (terbium) contained in the magnet, but these substances are expensive. Therefore, by reducing the coercive force inside the magnet, the contents of Dy and Tb can be reduced inside the magnet 5 and the cost performance of the motor can be improved. A magnet having a lower coercive force as shown in FIG. 3 can be manufactured by a method called grain boundary diffusion.

  (Second Embodiment) Next, the motor 52 of the second embodiment will be described with reference to FIGS. A side view and a cross-sectional view of the motor 52 are the same as those of the motor 2 shown in FIG. FIG. 4 is a longitudinal sectional view of the rotor 53 of the motor 52, and FIG. 5 is a longitudinal sectional view of the magnet 55 inserted into the rotor 53. As shown in FIGS. 4 and 5, the magnet 55 is divided into four magnet pieces 55a-55d. The plurality of magnet pieces 55a to 55d have different magnetic characteristics. In FIG. 4, the difference in magnetic characteristics is represented by the difference in hatching.

  The magnet pieces 55a to 55d are arranged in a line in the magnet insertion hole 4a extending along the rotor axis CL. A pair of adjacent magnet pieces face each other at parallel end faces, and the plurality of magnet pieces 55a to 55d are arranged without gaps. An end face where adjacent magnets face each other is hereinafter referred to as an opposing face. The facing surfaces of any pair of adjacent magnets are different in shape from the facing surfaces of another pair of adjacent magnets. Furthermore, any of the opposing surfaces is also non-parallel to the end surface St of the magnet 55 and has a different shape. Here, the shape is a three-dimensional shape. To be more strictly defined, for example, relative to an axis orthogonal plane with respect to a plane orthogonal to the rotor axis CL (axis orthogonal plane), That is, the shape is different on all facing surfaces. In other words, the facing surfaces of any pair of magnets and the end surface St are non-parallel to the facing surfaces of other adjacent pairs of magnets.

  An example of the difference between the opposing surfaces will be described with reference to FIG. Opposing surfaces Sa of the pair of magnet pieces 55a and 55b are planes inclined with respect to the rotor axis CL. In other words, the facing surface Sa is inclined with respect to a plane orthogonal to the axis line CL. The “opposite surface” includes both the surface of one adjacent magnet and the surface of the other magnet facing the surface, and strictly speaking, “a pair of opposing surfaces” is appropriate. However, in this specification, “a pair of facing surfaces” is simply referred to as “facing surfaces”. Symbols Sa (and symbols Sb and Sc) in FIGS. 4 and 5 indicate the pair of opposed surfaces. The opposing surfaces Sb of the magnet pieces 55b and 55c, which are another pair of magnet pieces, are flat surfaces that are inclined with respect to the rotor axis CL, and the inclination angle is different from that of the opposing surface Sa. Further, the opposing surface Sc of the magnet pieces 55c and 55d, which is another pair of magnet pieces, is a curved surface that protrudes toward the magnet piece 55d. Thus, the opposing surfaces of any pair of opposing magnets are different in shape (inclination or curved shape) from the opposing surfaces of other adjacent pairs of magnets. Furthermore, the shape of each facing surface is also different from the outermost end surface St of the magnet 55 in the axis CL direction. Due to this feature, if the order in which the plurality of magnet pieces 55a to 55d are put into the magnet insertion hole 4a is incorrect, a pair of opposing surfaces of adjacent magnet pieces are not parallel and a gap is generated. Therefore, the operator who inserts the magnet pieces can immediately notice that the insertion order is wrong. Therefore, in the motor 52 of the second embodiment, it becomes easy to insert a plurality of magnets whose order of insertion into the magnet insertion hole 4a of the rotor core 4 is predetermined.

  As shown in FIG. 5, the magnet 55 composed of four magnet pieces 55 a to 55 d has different magnetic force characteristics depending on the part. However, among the four magnet pieces, the magnetic properties of the inner magnet pieces 55b and 55c differ depending on the part in the direction orthogonal to the axis CL, but are uniform in the direction along the axis CL. Therefore, the magnet pieces 55b and 55c have the same magnetic property as the whole magnet even if the arrangement is changed. As in this example, when the shapes of all the facing surfaces are different, if one wrong insertion order into the magnet insertion hole, all the magnet pieces will not fit in the magnet insertion hole, and it was immediately discovered that the order was incorrect. Is done. Therefore, the technique of this embodiment is also effective when the magnetic force characteristics are more complicated than those shown in FIG.

  If all the magnet pieces have the same shape and are inserted in the wrong order, the following problems occur. As shown in FIG. 1B, the rotor core 4 is provided with a plurality of magnets 5 around the rotor axis CL. If magnets in which the magnet pieces are inserted in the wrong order are mixed in the plurality of magnets 5, imbalance occurs in the magnetic force characteristics in the circumferential direction of the rotor core 4. An unbalance in the magnetic characteristics of the rotor core 4 is not preferable because it causes an unbalance in the rotation of the rotor core 4.

  Points to be noted regarding the motor described in the embodiment will be described. In other words, the magnets 5 and 55 reaching from the one end in the axis CL direction of the rotor core 4 to the other end are divided into a plurality of magnet pieces. Any number of divisions may be used. However, the technique disclosed in the present specification is a technique for preventing the arrangement order of the magnet pieces arranged in a row from being mistaken, and is therefore suitable for a motor using magnet pieces divided into three or more pieces.

  The position-dependent magnetic characteristics shown in FIGS. 3 and 5 are examples. The technique disclosed in this specification is, for example, an arrangement of magnet pieces that should be arranged at the end in the axial direction of the rotor core in a plurality of magnet pieces arranged in a line along the axis CL in the rotor core. It is a technology that prevents the position from being mistaken. The present specification also discloses a technique obtained by further improving the above technique. The technique is a technique for preventing the arrangement order of a plurality of magnet pieces arranged in a line along the axis CL in the rotor core from being mistaken. In that case, the position dependency of the magnet piece in the rotor axial direction may be any. For example, a series of magnet pieces arranged in a line may have a position dependency that a magnet piece located at an end in the axial direction of the rotor core is stronger than a magnet piece located at the center in the axial direction. .

  In addition, when the insertion order of each magnet is determined in advance in a plurality of four or more magnets, the opposing surfaces of a pair of adjacent magnets in the magnet insertion hole are parallel to each other. In addition, the facing surfaces of the pair of magnets are not parallel to the facing surfaces of the other pair of magnets and the outermost end surface (the end surface that is originally positioned on the outermost side in the axial direction when inserted into the magnet insertion hole). There should be. In other words, even if any two pairs of magnets are selected, the facing surfaces of the pair of magnets and the facing surfaces of the other pair of magnets may be non-parallel. In this case, if four or more magnets are inserted into the magnet insertion hole in the wrong order, the facing surfaces of adjacent magnets face each other at different angles, and a gap is created between the magnets. Does not fit properly. Therefore, the assembly operator can immediately notice that the insertion order of the magnets is wrong.

  Since there are two opposing surfaces in the pair of magnets, strictly speaking, it means that the pair of opposing surfaces of the pair of magnets are parallel. In this specification, in order to simplify the expression and help understanding, the “pair” of the pair of facing surfaces is omitted. Moreover, although the opposing surface (a pair of opposing surface) of a pair of adjacent magnet needs to be parallel, it does not need to be a plane and may be curving. The motor magnet disclosed in this specification is expressed mathematically as follows. The pair of facing surfaces of each pair of adjacent magnets are parallel, and the pair of facing surfaces of all the pair of adjacent magnets have different three-dimensional shapes.

  According to the technology of the second embodiment, regarding a motor in which a plurality of magnets having different coercive forces are arranged in one magnet insertion hole of the rotor, it is possible to easily prevent the insertion order of the plurality of magnets having different coercive forces from being wrong. Can do.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2, 52: Motor 3, 53: Rotor 4: Rotor core 4a: Magnet insertion hole 5, 55: Magnets 5a, 5b, 5c, 55a, 55b, 55c, 55d: Magnet piece 12: Shaft 13: Nut 14: End plate CL : Rotor axis Ma: High coercive force region Mb: Medium coercive force region Mc: Low coercive force regions Sa, Sb, Sc: Opposing surfaces (end surfaces)
St: outermost end face

Claims (1)

A rotor having a magnet insertion hole extending in the rotor axial direction;
A plurality of magnets having three or more different magnetic properties inserted in the magnet insertion hole side by side in the rotor axial direction,
In the rotating machine, the outermost end surface in the rotor axial direction and the other end surface in the rotor axial direction other than the outermost end surface are non-parallel to the plurality of magnets.